PD-1 stands for Programmed Death Receptor 1 and its English name is Programmed Death 1. It is an important immunosuppressive molecule and is a member of the CD28 superfamily. Immunomodulation targeting PD-1 has important significance in anti-tumor, anti-infection, anti-autoimmune diseases and organ transplant survival. Its ligand PD-L1 can also be used as a target, and the corresponding antibody can also play the same role.
PD-L1 is the full name of programmed death receptor-ligand 1 , the English name of Programmed Cell Death-Ligand 1 , is the first type of transmembrane protein with a size of 40kDa. Under normal circumstances, the immune system responds to foreign antigens that accumulate in the lymph nodes or spleen, promoting the proliferation of antigen-specific T cells. The combination of programmed cell death receptor-1 (PD-1) and apoptosis-ligand 1 (PD-L1) can transmit inhibitory signals and reduce the proliferation of T cells.
My understanding, please correct me if something is wrong (informal expression) :
Sometimes people have some cells that are mutated, and then the cells grow wildly (we call them tumors ). The cell growth absorbs the surrounding nutrients, causing other normal cells to become malnourished or even die, but there is a fault tolerance mechanism inside this complex system , It will let a kind of white blood cells (we call them T cells ) to eliminate tumors and restore people to a healthy state.
But this T cell is a stunned head. When he killed the tumor cells, he gradually killed his red eyes. He also killed the normal cells.
If this human system can't think about it, we have to find a way to wake up the stunned head, so it produces a substance called "PD-1" (T cell comes) to act as a tranquilizer to calm down the T cells : Little T, do n’t go mad, calm down, your brothers let you crash, remember not to dry yourself, you ca n’t stop it, dry the tumor, remember the dry tumor cells.
As the saying goes, the height of the foot is high, the height of the magic is high, the tumor cells thought of an idea, and used a beautiful hand. The beauty of the river and lake is called " PD-L1 ". After that, you know, every time the T cells are going to destroy the tumor cells, they will first encounter the beauty of " PD-L1 ", which makes his fighter jet drop sharply, and his mind is not clear, this' " PD-1 "The tranquilizer is also useless.
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The internal system of the human body has found it powerless, but the human brain is not convinced to lose. He wants to live another 500 years. . .
So he made two things called antibodies. One antibody combined with "PD-1" , stimulated "PD-1" to work, played a calming role, and allowed T cells to clearly identify tumor cells . The other antibody is combined with "PD-L1" , so that the beautiful woman "PD-L1" will be robbed before the T cells inspect the tumor cells, then the T cells are not tempted by the beautiful women and can stay awake and kill the tumor cells .
Formal expression:
The PD-L1 we mentioned here is a protein expressed on the cell surface, also known as B7-H1 protein, which is edited and expressed by the CD274 gene. It can combine with PD-1 and B7.1 on effector T cells to transmit immune suppression signals and suppress the activity of immune effector T cells. PD-L1 is expressed in many types of cells, including placenta, vascular endothelial cells, islet cells, muscle, liver cells, epithelial cells, mesenchymal stem cells, and B cells, T cells, dendritic cells, macrophages, Mast cells. The expression of PD-L1 on the surface of tumor cells has become a driving factor for tumor growth due to tumor escape from immune cell chase.
Introduction process
Cancer cells are like little demons that have removed their seals. They are no longer under the control of the human body. One becomes two, two becomes four, and four becomes eight. The characteristic of cancer cells is uncontrolled growth.
The human immune system is like a human fighter, specializing in killing bacteria and viruses that invade the human body .... but it seems to be useless for cancer cells.
This silver fighter is a cytotoxic T cell, which is a type of white blood cell that can detect infected or mutated cells
When he finds these cells, he emits toxins and starts his self-destruction process (programmed cell death)
But T cells can't kill all the way, killing red eyes, people block killing, Buddha blocks killing Buddha, and finally kill normal healthy cells.
Fortunately, activating a molecule called PD-1 can turn off T cells and protect normal cells from attack
But smart cancer cells also express the PD-L1 receptor, which binds to PD-1 on the surface of T cells, confusing T cells
The following is the time when monoclonal antibodies come into play, which is the focus of this article. How do these world-famous antibodies play an anti-tumor effect? At present, there are mainly two kinds of antibodies, one binds to PD-1 on the surface of T cells, rejuvenating the past.
The other antibody binds to PD-L1 on the surface of tumor cells, so that tumor cells cannot confuse T cells, so that the switch of T cells remains open and awake, and can always remember the mission and never forget the original intention.
In the end, T cells surrounded various tumor cells and won a great victory.
